How to convert ImageSource to Byte array?

Question

I use LeadTools for scanning.

I want to convert scanning image to byte.

void twainSession_AcquirePage(object sender, TwainAcquirePageEventArgs e)
 {
         


        

Answer 1

I ran into this issue in Xamarin.Forms where I needed to convert a taken photo from the camera into a Byte array. After spending days trying to find out how, I saw this solution in the Xamarin forums.

var photo = await CrossMedia.Current.TakePhotoAsync(new Plugin.Media.Abstractions.StoreCameraMediaOptions() { });

byte[] imageArray = null;

using (MemoryStream memory = new MemoryStream()) {

    Stream stream = photo.GetStream();
    stream.CopyTo(memory);
    imageArray = memory.ToArray();
}

Source: https://forums.xamarin.com/discussion/156236/how-to-get-the-bytes-from-the-imagesource-in-xamarin-forms

Answer 2

It seems that you can cast the result from .ConvertToSource to a BitmapSource instead of a ImageSource.

I am not 100% sure how this translate to your case but the doc from LeadTools show this VB sample:

   Dim source As BitmapSource
   Using raster As RasterImage = RasterImageConverter.ConvertFromSource(bitmap, ConvertFromSourceOptions.None)
      Console.WriteLine("Converted to RasterImage, bits/pixel is {0} and order is {1}", raster.BitsPerPixel, raster.Order)

      ' Perform image processing on the raster image using LEADTOOLS
      Dim cmd As New FlipCommand(False)
      cmd.Run(raster)

      ' Convert the image back to WPF using default options
      source = DirectCast(RasterImageConverter.ConvertToSource(raster, ConvertToSourceOptions.None), BitmapSource)
   End Using

I think it should be like

BitmapSource source = RasterImageConverter.ConvertToSource(ScanImage, ConvertToSourceOptions.None) as BitmapSource;

Then you can copy the BitmapSource pixels with BitmapSource.CopyPixels

Answer 3

If you are using Xamarin, you can use this:

public byte[] ImageSourceToBytes(ImageSource imageSource)
{
    StreamImageSource streamImageSource = (StreamImageSource)imageSource;
    System.Threading.CancellationToken cancellationToken = 
    System.Threading.CancellationToken.None;
    Task<Stream> task = streamImageSource.Stream(cancellationToken);
    Stream stream = task.Result;
    byte[] bytesAvailable = new byte[stream.Length];
    stream.Read(bytesAvailable, 0, bytesAvailable.Length);
    return bytesAvailable;
}

Answer 4

I use use a MemoryStream:

var source = RasterImageConverter.ConvertToSource(ScanImage, ConvertToSourceOptions.None) as BitmapSource;
byte[] data;
JpegBitmapEncoder encoder = new JpegBitmapEncoder();
encoder.Frames.Add(BitmapFrame.Create(source));
using (MemoryStream ms = new MemoryStream())
{
   encoder.Save(ms);
   data = ms.ToArray();
}

Answer 5

I use this class to work with Image in WPF

public static class ImageHelper
    {
        /// <summary>
        /// ImageSource to bytes
        /// </summary>
        /// <param name="encoder"></param>
        /// <param name="imageSource"></param>
        /// <returns></returns>
        public static byte[] ImageSourceToBytes(BitmapEncoder encoder, ImageSource imageSource)
        {
            byte[] bytes = null;
            var bitmapSource = imageSource as BitmapSource;

            if (bitmapSource != null)
            {
                encoder.Frames.Add(BitmapFrame.Create(bitmapSource));

                using (var stream = new MemoryStream())
                {
                    encoder.Save(stream);
                    bytes = stream.ToArray();
                }
            }

            return bytes;
        }

        [DllImport("gdi32.dll")]
        [return: MarshalAs(UnmanagedType.Bool)]
        internal static extern bool DeleteObject(IntPtr value);

        public static BitmapSource GetImageStream(Image myImage)
        {
            var bitmap = new Bitmap(myImage);
            IntPtr bmpPt = bitmap.GetHbitmap();
            BitmapSource bitmapSource =
             System.Windows.Interop.Imaging.CreateBitmapSourceFromHBitmap(
                   bmpPt,
                   IntPtr.Zero,
                   Int32Rect.Empty,
                   BitmapSizeOptions.FromEmptyOptions());

            //freeze bitmapSource and clear memory to avoid memory leaks
            bitmapSource.Freeze();
            DeleteObject(bmpPt);

            return bitmapSource;
        }

        /// <summary>
        /// Convert String to ImageFormat
        /// </summary>
        /// <param name="format"></param>
        /// <returns></returns>
        public static System.Drawing.Imaging.ImageFormat ImageFormatFromString(string format)
        {
            if (format.Equals("Jpg"))
                format = "Jpeg";
            Type type = typeof(System.Drawing.Imaging.ImageFormat);
            BindingFlags flags = BindingFlags.GetProperty;
            object o = type.InvokeMember(format, flags, null, type, null);
            return (System.Drawing.Imaging.ImageFormat)o;
        }

        /// <summary>
        /// Read image from path
        /// </summary>
        /// <param name="imageFile"></param>
        /// <param name="imageFormat"></param>
        /// <returns></returns>
        public static byte[] BytesFromImage(String imageFile, System.Drawing.Imaging.ImageFormat imageFormat)
        {
            MemoryStream ms = new MemoryStream();
            Image img = Image.FromFile(imageFile);
            img.Save(ms, imageFormat);
            return ms.ToArray();
        }

        /// <summary>
        /// Convert image to byte array
        /// </summary>
        /// <param name="imageIn"></param>
        /// <param name="imageFormat"></param>
        /// <returns></returns>
        public static byte[] ImageToByteArray(System.Drawing.Image imageIn, System.Drawing.Imaging.ImageFormat imageFormat)
        {
            MemoryStream ms = new MemoryStream();
            imageIn.Save(ms, imageFormat);
            return ms.ToArray();
        }

        /// <summary>
        /// Byte array to photo
        /// </summary>
        /// <param name="byteArrayIn"></param>
        /// <returns></returns>
        public static Image ByteArrayToImage(byte[] byteArrayIn)
        {
            MemoryStream ms = new MemoryStream(byteArrayIn);
            Image returnImage = Image.FromStream(ms);
            return returnImage;
        }
    }

So try different approaches and modernize this class as you need.

Answer 6

Unless you explicitly need an ImageSource object, there's no need to convert to one. You can get a byte array containing the pixel data directly from Leadtools.RasterImage using this code:

int totalPixelBytes = e.Image.BytesPerLine * e.Image.Height;
byte[] byteArray = new byte[totalPixelBytes];
e.Image.GetRow(0, byteArray, 0, totalPixelBytes);

Note that this gives you only the raw pixel data.

If you need a memory stream or byte array that contains a complete image such as JPEG, you also do not need to convert to source. You can use the Leadtools.RasterCodecs class like this:

RasterCodecs codecs = new RasterCodecs();
System.IO.MemoryStream memStream = new System.IO.MemoryStream();
codecs.Save(e.Image, memStream, RasterImageFormat.Jpeg, 24);